Sealing-in machine for tubular double-ended lamps



Nov. 20, 1951 R T N 2,575,746

SEALING-IN MACHINE FOR TUBULAR DOUBLE-ENDED LAMPS Filed Jan. 11, 1947 2 SHEETSSHEET 1' lTl\/TYL'OTI PauL O. Gav-tun, b9 0W C. 1

His Attovne Nov. 20, 1951 I P. 0! CARTUN 2,575,746

SEALING-IN MACHINE FOR TUBULAR DOUBLE-ENDED LAMPS Filed Jan. 11, 1947 2 SHEETS-Si-IEET 2 Figs.

lnveni'or:

PauL O. Cav cun,

His Af irovneg.

Patented Nov. 20, 1951 UNITED STATES PATENT OFFICE SEALING-IN MACHINE FOR DOUBLE-ENDED LAMPS Paul 0. Cartun, Cleveland Heights, Ohio, assignor to General :Electric Company, :a corporation of New York Application January/111, 1947, Serial No. "721,529

14 Claims.

One object of my invention is to provide apparatus for gripping and holding the closure elements and the tubular envelope of electrical devices in sealing relation and for fusing said elements and said envelope together. The meat sealing apparatus having such a construction I facilitates the assembly and handling of the various parts of theelectrical'devices and assures proper and uniform sealingof the closure elements and-envelope incommercial manufacturing'practice.

Another object of my invention is to provide apparatus for simultaneously sealin closure elements to opposite ends of a tubular vitreous envelope and therebymaterially reduce the handling of the closure elements and the envelope. Heretofore considerable diificulty, breakage and expense has resulted in that theclosure elements were sealed to opposite ends ofthe tubular envelope'in-separate operations between which said envelope was removed, turned end-for-end and then reinserted in the sealing apparatus. Inas much as many of such envelopes are very long, 96 inches in some instances, the difficulty and time consuming factor of manipulating the envelopes comprises an important factor in the cost of'the sealing operation. The diilicultyof manipulating theglong envelopes is increased bythe presence of the heated seaL-and by the care required toprevent breakage of the 'fragile "erohaust tube at the end of the envelope.

Another object of my invention is to-provide apparatus for simultaneously sealing closure elementsto opposite ends of'a tubular envelope disposed in -a horizontal position, and associated -apparatusto materially increase the-convenience,

speed andsatis'factory performance of the sealing operation. 'Thegenerally satisfactory performance of the sealing operation in commercial manufacture requires that the seals be made properly and, in addition, that the handling of 2 parts be kept to'a minimum and that the entire operation be readily performable.

"Still other objects and advantages of myrinvention will appear from the 'following detailed description of species thereofand from the drawing.

In the drawing, Fig. 1 is aside elevation of one species of sealing apparatus comprising myinventionyl ig. 2 is a vertical section'throug-h the apparatus along line 2-4 of'Fig. 1 in the -direc--' tion indicated; 'Fig. 3 is a 'longltudlnal section through the head end of the apparatus along line 3-3 of Fig. 2 in the direction indicated; Fig. 4 is a longitudinalsection through the holder, the burner and the adjacent portion of the head at one end of the apparatus with a closure element and end portion of an envelope in sealing relation thereto; and Fig. 5 is a section-correspending to Fig. 4. of a modification of my apparatusholding a modified closure element and envelope end.

'As shown in'Figs. 1, 2-and3 my-apparatus comprises six heads I spaced about the horizontal shaft 2 with their component parts mounted on the turrets 3 and A at opposite ends thereof'and on the spiders 5, 6 and 1 located therebetween, Each head I comprises a series (three) of pairs of jaws 12, land a pair of holders ,9, 9, and'is adapted to. hold a closure element inthe form of a glassstem type electrode mount 8 on each of the holders 3.99 on the hollow spindles I0 carried by the turrets '3 and 4 and to support in alignment. therebetween a relatively long tubular envelope H held bycorresponding pairs of jaws l2 and Hon the spiders-5, B and I. Clockwise, (Fig.2) indexing movements of the shaft 2 which issupported atthe head end by the balibe'arings 14-min the head stock I5 carried by the bed 16 and at the tail end by corresponding bearings (notshown) in the tail stock I! carried by saidgbed. wadvan all par sof he h ads in turn, to. successive work stations. Movement of the shaft 2 is :controlled throu h the engagement of a barrel cam 18 with one or more of the rollers H2011 the spider '20 Jon the head end of said-shaft 2. Th -cam lB-isrotated by themain drive shaft 2 I and is. grooved to-advance a roller I9 and accordingly the heads iduringa portion of; 11385120- tation. A portion ofthe cam it of uniform shape separates two of the rollers l9 and holds the heads I at definite locations during'the remainder of the rotation of the cam. -Means-(not shown) such as an electric motor and speed reducer are preferably provided 1 for :turning the mainhdrivo shaft 2I to actuate the entire apparatus at a uniform rate.

The apparatus is preferably operated with the assistance of two operators who take positions adjacent the head and tail stocks I5 and I1, respectively, at the near side (Fig. 1) of the apparatus, and who introduce the electrode mounts 8 and envelope II into the heads I at station A which is the initial station taken in the cycle of operation. Each operator places the electrode mount 8 on the holder 9 (Fig.4) by threading the end of the exhaust tube 22 and theextending ends of the leading in wires 23 and 24 through the central opening in said holder 9 and then moving said electrode mountB so that the cavity formed by the stem tube 25 passes over the head of the holder and the flanged portion of the stem tube 25 abuts against the flange 21 at the rear of the said head of holder 9. The head and adjacent portion of the holder 9 are divided into e four resilient finger portions by slits, such as that shown at 28; at 90 degree intervals, to constitute a sort of coll t chuck in which the said fingers are compressed by the inner walls of the cavity in the stem tube 25 so that they tend to expand and thereby engage said tube 25 with suflicient pressure and friction to hold the electrode mount 8 securely in place.

After feeding the ele trode mounts 8-8 into thehead' I, the operators cooperate in effecting the opening of the three pairs of jaws I2 and I3 thereof on the s iders 5, 6 and I by pressing a ainst one of. the three coupled control levers 29 of; the actuating means of any of the said pairs of jaws I2 and I3 and then releasing the end-most envelope II of the supply thereof carried on the rails 30-30 so that said envelope rolls down said rails 30-39 and into the pairs of jaws I2 and 3. Thereafter, the pressure against the control lever 29 is released and the jaws I2 and I3 which are pivoted on pins 3I3I on the spi ers 5, 6 and I are closed on the envelope II by the movement effected in each control lever-29 by the contraction force of springs 32 extending between said levers 29 and posts in the spiders 5, 6 and '1. The jaws I2 and I3 of each pair are influenced by the movement of a wed e 33 on the end of a control lever 29 into position between the ends thereof and close equally so that the envelope-I I is held in proper alignment with the holders 9 and the electrode mounts 88. The three control levers 29 of eachhead I are coupled together through a rod 34 to which they are fastened and which is carried by bearings in the spiders 5, 6 and I and, accordingly, they actuate all three pairs of jaws I2, I3 of each head I upon manipulation of any One of the levers. The contractingforce of the springs 35 which extend between a post in each of-the jaws I2 and I3 influence said jaws I2 and I3 so that they take positions determined by the positions of the wedges 33. The envelope II is positioned longitudinally within the head I by the extending end portions 35-36 of the sides of the rails 3fl3fl. I

The operations of the apparatus relating directly to the sealing functions thereof begin with the indexing movement of the head I to station B and are initiated by movements of both holders 9 toward the spiders 5, Band I so that the electrode mounts 3 are carried into the open ends of the envelope I I and th rim portions of the flanges 23 of the stem tubes 25 therefore seated tightly against the rims of the open ends of the envelope II. The movements of the holders 9; are cau ed 4 by passage of the rollers 31 on the collars 38 on the opposite ends of the spindles I0 therefrom onto the inclined surfaces of the stationary cams 39 and then beyond said cams 39, which passage allows the expansion force of springs 46 located about portions of the spindles Iil between turrets 3-and 4 and the burners M on the spindles to move said spindles I0 and holders Sasdescribed. Each holder 9 is at such times under the constant resilient influence of the expansion force of the spring 40 which force keeps the engaged surfaces (Fig. 4) of the electrode mounts 8 and the envelope I I in intimate contact.

vAnother operation occurs during the indexing movement of the head I to station B, the operacover plate 43 of said burners 4| against the flanges 25 of the stem tubes 25 and to a limited extent against the rim of the envelope II. Each burner 4| (Fig. 3) at the head end of the apparatus receives gas from a rotary valve through a connection made to a-separate opening 54 in the face of the rotating section 45 thereof, which is in engagement with the stationary section 46 thereof, through the pipe nipple 41, flexible hose 48 and pipe branch-connection 49. Corresponding burners 4| (Fig. 1) at the opposite end of the apparatus receive gas through pipe nipples 5|, flexible hoses 52, pipes 53 and the branchconnections 49 and are therefore operated in combination with the other burners II of the heads I. The gas connection terminates in the opening 44 in the rotary valve while the head I is located at station A as the opposite face of the stationary section 46 over which said opening 44 is located is solid. However, the indexof the head I to station B causes a corresponding move-; ment to the rotating section 45 of said valve which carries said opening 44 over the arcuate passage 54 (Figs. 2 and 3) in said stationary section 46 which passage 54 is connected to a main gas supply source through pipe 55. Pilot burners .(not shown) located along the path of movement of the burners 4i cause the gas discharged thereby to be ignited. Proper contact between the moving and stationary sections 45 and 46 of the rotary valve is assured by the pressure of the expansion force of springs 56 located in wells in the head stock I5 behind the stationary section 45 whereas proper rotation and fixation of the moving and stationary sections 45 and 46 is caused by the key 51 which connects said moving section 55 to shaft 2 and the stud 58 which extends from said stationary section 45 to a confining opening in the head stock I5.

When the-head 5 takes station B, the outer edges of the flanges 25 of the stem tubes 25 of the electrode mounts 8-8, at both ends thereof and the adjacent rim portions of the envelope II are being heated by the burners 4I--4I and moderate pressure is being applied against each stem tube 25-25 through each holder 9 to keep the flanges in intimate contact with'the ends of the envelope I I. Any irregularity of the mating surfaces cannot cause a longitudinal displacement of the envelope II since it is held securely by the jaws I2 and IS on the spiders 5, 3 and l.

The heating operation continues during the further indexing movement of the head I which takes the electrode mounts 8-8 and envelope II through stations C, D and E, in turn, and gradu-. ally fuses and seals thestem flanges 26-25 to said envelope II. In the co urseofthe indexing movements, thecgradual :sottening; of --.stem

flanges :2 6*.216 and the adjacent-portions )O the envelope I "allows. the pressure of engagement ofuthe .holders 9-:9 to producemovementin said holders iSe-HIQ and the electrode mounts lie-.18 causingithe workingof the full periphery of the sealed area into satisfactoryacondition obviating all minor irregularities in these l parts. The movement of the holders 9-9 .occursvprior 31130 the advancewoi rthehead 1| winto stationiE and reaches its limit when the collars"38- :38 on the opposite ends of the spindles.*l:-zl0.seat against the turrets 3and4. In the advanceof the head I to station *E, the holders 9+9 are drawnback in adirection away iromthe envelopeaifl short distances by thepassage .oi the rollers 4-31- 3? on-collars 3838 onto the portionsv59..-j59 of cams 39-39and a jet of --air is "directed up through the hollow interior ofspindles .lfl- -lll and the open end of the exhaust tubes 2222 to the interior of the-envelope H by the stationary pipes-Ell, 60. I'Ihecombined pull of the holders 9, Spthrough theirfrictional engagement with the stem tubes 25-25, and the pressure of the airwithin the envelope I'l -causes the stem tubes 25 to be displaced as theyremain seated on-the holders *99 while the flanges 26 and seals of the now completely assembled lampare worked to slightly different shape. This working-operation and the annealing action of the fires from the burners 41-41 which are of reduced intensity at stationE retard the cooling and relieve the strains with-in the seals and the adjacent portionof the lamp so that very strong and satisfactory seals result. "The reducedstrength of the flames from the burners H-4 results from movement of the passage 44 in the moving section .5 of the rotary valve over a portion 6! (Fig. 2) of the arcuate passage 54 in the stationary sectiontfi of the valve which is separated from the main portion by the -restrictions! so thatflow of :gas to said burners-4l'-4l is-materially reduced.

I The indexing -movement-of the head I from.

station to 'F turns the movingsection of.

is disconnectedfromth passage causing the sealing fires to be extinguished. The indexing movement also carries-the rollers 31-31 on the collars 38-38 onto the highest parts of the cams 39-39 causing the spindles |0-I0-and holders 9-9 to move his direction away from the lamp so that said holders 9-9 are separated therefrom. The sealed portions of the lamp are suificiently cool at such times so as not tobe deformed by the pull of the holders 9-9.

At station F, the last station taken by the head i in one cycle of operation of the apparatus, the pairs of jaws lZand ill on spiders 5,6 and l are opened by the operators so as to effect the release of the lampand said lamp is shifted longitudinally andlaterally .50 as to lie-separated. and. mo ed.m nim-ap r tus- The per tors press against one of the control levers 29 to release the lamp, and then slide saidlamp. endwise to remove theexhaust tube :.22eat one end thereof completely from the associatedsholder .9,

shift it inthe opposite direction-to separate the-exhausttube zz at theopposite end from the other holder 9. The -removed lamp is rested on the sloping surface of 'the -taibles63 and a rolls :therealon to the .nextmanufacturing: op ration ;(not shown) ;In certain instances diirerently formedelectrodemounts, oneof whichis not provided with anexhaust tube, are sealed to opposite endsnof the envelope II. In such instances, the pipe at one end of the apparatus is dispensed with but otherwise the sealing operation is the same as described above.

In still other instances, Where closure members in the form of metal discs 64, such as that shown in Fig. 5, are to be sealed over opposite ends of the tubular envelope ll, use is made of a modified head having differently shaped holders and burners better suited to hold and heat said metal discs. The metal disc 6 as shown at oneend of the lamp in Fig. 5 .has a rounded cavity or indented portion 65 at the center and is mounted on the holder 66 by being slipped over the head tl thereof to the extent permitted by the flange-68. In this particular instance the head firl .andadjacent portion "of the holder 166 is rslitcas a-t 65 into three fingers which are resiliently compressible :to engage the circular disc 64 with sufficient friction to hold it iinuplace. The :disczfi' i is provided with an exhaust tube" 10 fusedthereto around an opening ll at the center of the cavity -:in the disc and extending .into the rpassageflf! of. the holder 66. The 'burner' 13 differs from that previously described in the location of the discharge openings 'M in the cover plate l5 thereof, which openings 14 are arranged to direct flames against .the disc "-54. The pressure of engagement of the;disc :64 with the end of :thevenvelope .l..| 'lllithe :normal operation of the apparatus assures positive engagement and sufficient heatexohange between thedisc E i and envelope I i to effect'the fusion of the latter and noua kirv of the seal shown in Fig. 5.

"What I claim as new and desire to secure by LettersPa'tent of the United States is:

1.. Apparatus .for sealing closure elements, each having a-cavity a t the center thereof, to opposite ends of a tubular envelope comprising spaced turrets rotatable on a common axisaa spider located therebetween and rotatable on "the same axis, a pluralitywof heads at spaced intervals about'the axis of rotation each compris ing movable holder mountedon each turret and having a resiliently compressible end portion forsupporting and gripping a closure element through frictional engagement with the walls of the cavity kinsaid closure element and means mounted on the spider for supporting the tubular envelopeobetween and in alignment with the holders, means in engagement withthe turrets and the .spider'for icausing the corresponding rotation thereof about the common axis to advance'the heads to a plurality of stations in turn,.means engaging the holders for moving said holders-toward and away from each lotherat separate stations to bring the closure elements inrproper sealing relation to the ends of "the tuhularenvelope and to thereafter separate said holders from the closure-elements, and heating means located in operative relation to the holders for r fusing together the closure elements and the ends-0f the'tubu-lar envelope at other stations.

2. Apparatus for sealing closureelements, each having acavity at the center thereof, to opposite ends of a tubular envelope comprising a horizontally disposed rotatable shaft, turrets mounted on the shaft, aspider mounted onthe shaftbetweensaid turrets, a plurality of headsat spaced intervals about the shaft each comprising a movable holder mounted on each turret and having a resiliently compressible end portion for supporting and gripping a closure element through frictional engagement with the walls of the cavity in said closure element and means mounted on the spider for supporting the tubular envelope in alignment with the holders, support means engaging the opposite ends of the shaft, means engaging the shaft for causing the rotation thereof to advance the heads to a plurality of stations in turn, means in engagement with the holders for moving said holders toward and away from each other at separate stations to bring the closure elements in proper sealing relation to the ends of the tubular envelope and to thereafter separate said holders from the 010st ure elements, and heating means located in operative relation to the holders for fusing together the closure elements and the ends of the tubular envelope at other stations.

3. Apparatus for sealing closure elements, each having a cavity at the center thereof, to opposite ends of a tubular envelope comprising spaced turrets rotatable on a common axis, a spider located between said turrets and rotatable on the same axis, a plurality of heads at spaced intervals about the axis of rotation each comprising a longitudinally movable spindle supported by each turret, a holder mounted on each spindle having a resiliently compressible end portion for supporting and gripping a closure element through frictional engagement with the walls of the cavity in said closure element, and means mounted on the spider for supporting the tubular envelope between and in alignment with the spindles, means in engagement with the turrets and the spider for causing the corresponding rotation thereof about the common axis to advance the heads to a plurality of stations in turn, means in engagement with the spindles for moving'said spindles toward and away from each other to bring the closure elements into engagement with the proper sealing relation to the ends of the tubular envelope and to thereafter separate the'holders from said closure elements, and burners mounted on the spindles adapted to direct heating flames against the closure elements for fusing together said closure elements and the tubular envelope.

4. Apparatus for sealing closure elements, each having a cavity at the center thereof, to opposite ends of a tubular envelope comprising spaced turrets rotatable on a common axis, a spider located between said turrets and rotatable on the same axis, a plurality of heads at spaced intervals about'the axis of rotation each comprising a longitudinally movable spindle supported by each turret, a holder mounted on each spindle having a resiliently compressible end portion for supporting and gripping a closure element through frictional engagement with the walls of the cavity in said closure element, means mounted on the spider for supporting the tubular envelope between and in alignment with the spindles, and resilient means in engagement with the spindles tending to move the holders toward each other, means in engagement with the turrets and the spider for causing the corresponding rotation thereof about the common axis to advance the heads to a plurality of stations in turn, means located along the course of movement of the heads for withdrawing the spindles away from each other to permit the placing of closure elements onto the holders and insertion of a tubular envelope therebetweeni in the support means therefor and for thereafter releasing said spindles to permit the resilient means to move them so that'the closure elements are advanced into engagement and proper sealing relation to the ends of the tubular envelope, and heating means in operative relation to the holders for fusing together the closure elements and the ends of the tubular envelope.

5. Apparatus for sealing closure elements, each having a cavity at the center thereof, to opposite ends of a tubular envelope comprising a head for supporting the closure elements and the tubular envelope in sealing relation, said head comprising spaced spindles movable toward and away from each other, holders mounted on the spindles having a plurality of compressible spring fingers for supporting and gripping the closure elements through frictional engagement with the walls of the cavities therein and having outwardly protruding means on at least one of the spring fingers of each holder abutted by said closure elements for positioning the said closure elements thereon, means between and in alignment with the spindles for supporting a tubular envelope with the ends adjacent the holders, burners mounted on the spindles adapted to direct heating flames against the closure elements for fusing together said'closure elements and the ends of the tubular envelope, and expansion springs surrounding portions of the spindles for moving the spindles toward each other and the closure elements into engagement and proper sealing relation to the ends of the tubular envelope, a carrier for advancing the head to 'a plurality of stations comprising a horizontally disposed rotatable shaft, spaced turrets mounted on the shaft for supporting the spindles of the head, a spider mounted on the shaft between said turrets for holding the envelope-supporting means, means engaging the shaft for causing the rotation thereof to advance the head, arotary valve mounted for actuation by the shaft to supply the burners with combustible gas during a portion of the rotation of said shaft during which the head is located at a station, and means engaging the spindles at other stations for moving the spindles farther away from each other to allow the closure elements and the envelope to be inserted and, after the sealing operation, to allow the removal thereof.

6. Apparatus for sealing closure elements, each having a cavity at the center thereof, to opposite ends of a tubular envelope comprising; a head including spaced and alignedspindles, resilient holders movably mounted in said spindles for supporting the closure elements by engagement withthe walls of the cavities therein, an'interposed tube supporting means for supporting said tubular envelope inalignment with said holders, and heating means associated with each holder;

a movable turret for supporting the said head,

and stationary cam means in the path of movement of said spindles for moving said holders lar envelope in alignment with said holders, and

heating means associated with each holder; a

movable turret for supporting the said head; and

stationary cam means in the path of movement of said spindles for moving said holders toward and away from said tube supporting means to carry'the closure elements in sealing relation to the ends of the tubular envelope and to there- 'after separate said holders from the closure eleheating means associated with each holderf a movable turret for supporting the said head;

stationary cam means in the path'of movement of said spindles for'm'oving said'holders toward and .awayfrom said tube supporting means to carry the" closure elements into sealing relation to the ends of the tubular envelope and to thereafter lsjeparate said holders from the" closure elements; and means for introducing compressed air into the said envelope concomitantly with the movement of said holders away from said tube supporting means.

9. Apparatus forsealirig closure elements to the opposite ends of a tubular envelope comprising support means for holding the tubular envelope, spaced opposed movable holders located on opposite sides of and in alignment with said support means for gripping respective closure elements and holding them in alignment with said envelope opposite the respective ends thereof, means mounting the holders for movement toward and away from said envelope support means, actuating means coacting with said holders to normally hold them in retracted position with the closure elements spaced from the ends of said envelop-e and to subsequently advance said holders toward each other to bring the closure elements into juxtaposition with and proper sealing relation to the ends of said envelope and, after sealing of the closure elements to the envelope, to separate said holders from the closure elements and withdraw said holders to their retracted position, and heating means associated with each holder for heating and fusing together the closure elements and the ends of the envelope.

10. Apparatus for sealing closure elements to the opposite ends of a tubular envelope comprising support means for tightly holding the tubular envelope against longitudinal movement therein, spaced opposed movable holders located on opposite sides of and in alignment with said support means for gripping respective closure elements and holding them in alignment with said envelope opposite the respective ends thereof, means mounting the holders for movement toward and away from said envelope support means, actuating means coacting with said holders to normally hold them in retracted position with the closure elements spaced from the ends of said envelope and to subsequently advance said holders toward each other to bring the closure elements into juxtaposition with and proper sealing relation to the ends of said envelope, and heating means associated with each holder for heating and fusing together the closure elements and the ends of the envelope, said actuating means being, further adapted to ad- 1'0 vancejthe holder's andassociated closure elements 2: furtneramount'toward each other from their illllllail sealing position upon softening of the closure elements andthe envelope endsfand, after sealing of the-closureelements to the envelope, to separate the holders from the" closure erem'ents and withdraw said holdei's totheir retracted position; i V

l lflpparatus ror sealing' closure elements to the oppcsit ends"of a tubular envelope comprisinguppc t'means for tightly holding the tubular en'veiope against longitudinal movement therein; spaced opposed movable holders located or'hoppo's to es of 'ai'id irralignment with-said support in rorfgr'ippihgrespective closure ere "ments and holding them in alignment with said envelopeopposite H e jrespective ends thereof, means mounting holders for movement" toward and away from said envelope support means; separate n eitmmee ea actuating means foreachf of said holders and coacting therewith to'normally hold them in retracted position with envelcpeand to subsequently advance said hold erssmiultaneousiy toward each other to bring the closure e ements into juxtaposition with and sure elements and the ends of" the'en'velop'e; said actuating means being further adapted to advance the holders and closure elements a further amount toward, each other from their initial Sealing position upon softening of the closure elements and the envelope ends and, after sealing of the closure elements to the envelope, to simultaneously separate the holders from the closure elements and withdraw said holders to their retracted position.

12. Apparatus for sealing closure elements to the opposite ends of a tubular envelope comprising support means for tightly holding the tubular envelope against longitudinal movement therein, spaced opposed movable holders located on opposite sides of and in alignment with said support means for gripping respective closure elements and holding them in alignment with said envelope opposite the respective ends thereof, means mounting the holders for movement toward and away from said envelope support means, resilient actuating means coacting with said holders to normally hold them in retracted position with the closure elements spaced from the ends of said envelope and to subsequently advance said holders toward each other to yieldably press the closure elements against the ends of said envelope and move them longitudinally inward of said envelope upon heating and softening of the closure elements in the envelope ends, and heating means associated with each holder for heating and fusing together the closure elements and the ends of said envelope, said actuating means being further adapted to separate the holders from the closure elements after sealing of the latter to the envelope and to withdraw said holders to their retracted position.

13. Apparatus for sealing closure elements, each having a cavity at the center thereof, to opposite ends of a tubular envelope comprising support means for holding the tubular envelope, spaced opposed movable holders located on opposite sides of and in alignment with said support means and each having a plurality of compressible spring fingers for supporting and gripping respective closure elements through fric- ,tional engagement with'the walls of the cavity therein and holding them in alignment with said -envelope opposite the respective ends thereof,

"means mounting the holders for movement to- :ward' and away from said envelope support I means, actuating means coacting ith said holders to normally hold them in retracted position "with the closure elements spaced from the ends of said envelope and to subsequently advance ,s'aid holders toward each other to bring the closure elements into juxtaposition with and elements andreturn the said holders to their normal retracted position, and heating means associated with each holder for heating and ,fusing together the closureelements and the ends of the envelope;

'14'LApparatus for" sealing closure elements,

positesides of and in alignment with saidsup- 'port means and each having'a resiliently comfpressible end portion'for supporting and gripping respective closure elements through 'frictional engagement with the walls of the cavities therein and holding them in sealing relation to the opposite ends of the envelope, heating means in :operative relation to said 'holdersifor fusing together the closure elements and the tubular envelope, means for introducing compressed air in the tubular envelope, and means operable coneomitantly' with the last-named means for mov- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS v Date Number Name 1,011,523 Swan Dec. 12, 1911 1 1,461,155 Madden et a1. July 10,1923 2,121,627 Donovan et a1 June 21, 1938 2,212,842 McGowan Aug. 27, 1940 2,364,673 Stuckert et al. Dec. 12, 1944 2,394,115 Snyder Feb. 5, 1945 2,417,361 Herzog Mar. 11, 1947 2,434,664 Malloy Jan. 20, 1948 2,455,317 Schneider Nov. 30, 1948 FOREIGN PATENTS Number Country Date 542,173 Germany Jan. 22, 1932 Certificate of Correction Patent No. 2,575,746 November 20, 1951 PAUL O. CARTUN It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 7, line 44, for the proper read and proper;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 1st day of April, A. D. 1952.

[sun] THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

